A386361 Number of partitions of n such that the least part occurs exactly (1/4)*(number of parts) times.
0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 5, 6, 9, 12, 16, 20, 26, 32, 41, 50, 62, 76, 93, 112, 136, 164, 197, 237, 283, 339, 403, 480, 569, 676, 799, 945, 1113, 1314, 1543, 1815, 2125, 2494, 2912, 3407, 3970, 4632, 5384, 6266, 7268, 8438, 9766, 11310, 13063, 15097, 17402
Offset: 1
Keywords
Programs
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Ruby
def partition(n, min, max) return [[]] if n == 0 [max, n].min.downto(min).flat_map{|i| partition(n - i, min, i).map{|rest| [i, *rest]}} end def A(n, k) cnt = 0 partition(n, 1, n).each{|ary| cnt += 1 if k * ary.count(ary.min) == ary.size } cnt end def A386361(n) (1..n).map{|i| A(i, 4)} end p A386361(40)